1. Technical Field
The present invention relates to machine tool rotary cutting tools in general, and to end mills in particular.
2. Background Information
A variety of end mills for use with rotating milling cutters are available and well known. Depending on design, such end mills are generally used in right hand cutting, right hand spiral and center cutting. Conventionally, these end mills are made from hardened steel, carbides, ceramics, etc. Standard end mills are supplied in two or more flute designs. A number of end mills have only one operating surface on the cutting face wall and one surface in the fluted area. Such end mills often have problems with chips adhering to the cutting face wall and do not achieve a cut as clean as an end mill with two operating surfaces. Another problem is chip clogging in the fluted area of the end mill.
U.S. Pat. No. 3,003,224 to Ribich discloses an end mill with two operating surfaces on the cutting face wall, a primary and a secondary tooth surface. End mills of the type disclosed within U.S. Pat. No. 3,003,224 provided an improved cut and better chip ejection than the state-of-the-art end mills then available. These end mills still have several deficiencies and limitations, particularly when used with the high speed machining capabilities of the present state of the art; e.g., the end mill has corner wear and edge chip problems; it often creates a loud, undesirable squeaking noise during use; it has a limited useful life; it cannot be effectively used above certain speeds; and it has less than desirable chip removal from the fluted area.
What is needed, therefore, is an end mill that has improved characteristics relative to the prior art end mills currently available.